I tentatively believe in a god. I was brought up in a fairly religious home. I think the world is compatible with reincarnation, karma, all that stuff.

I found university a little dispiriting. I thought I would enter the great halls of Plato, but instead I entered the halls of an intellectual sausage factory. I wanted to do something not on the main course, and chose the environment.

I'm an old member of Greenpeace. I worried intensely, as I think most of my friends did, that the world was coming apart.

Money spent on carbon cuts is money we can't use for effective investments in food aid, micronutrients, HIV/AIDS prevention, health and education infrastructure, and clean water and sanitation.

The obvious issue is providing clean drinking water and sanitation to every single human being on earth at the cost of little more than one year of the Kyoto treaty.

In the rich world, the environmental situation has improved dramatically. In the United States, the most important environmental indicator, particulate air pollution, has been cut by more than half since 1955, rivers and coastal waters have dramatically improved, and forests are increasing.

When thinking about the future, it is fashionable to be pessimistic. Yet the evidence unequivocally belies such pessimism. Over the past centuries, humanity's lot has improved dramatically - in the developed world, where it is rather obvious, but also in the developing world, where life expectancy has more than doubled in the past 100 years.